Ceramic capacitor having metal or metal oxide in side margin portions, and method of manufacturing the same

ABSTRACT

A multilayer ceramic capacitor includes: a ceramic body including dielectric layers and having first and second surfaces opposing each other, third and fourth surfaces connecting the first and second surfaces to each other, and fifth and sixth surfaces connected to the first to fourth surfaces and opposing each other; a plurality of internal electrodes disposed in the ceramic body, each exposed to the first and second surfaces and having one ends exposed to the third or fourth surface; and a first side margin portion and a second side margin portion disposed, respectively, on the first and second surfaces of the ceramic body, wherein a metal or a metal oxide is disposed in each of the first and second side margin portions, and a ratio of a diameter of the metal or the metal oxide to a thickness of the dielectric layer is 0.8 or less.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.16/173,581, filed on Oct. 29, 2018, which claims the benefit of priorityto Korean Patent Application No. 10-2018-0101999 filed on Aug. 29, 2018in the Korean Intellectual Property Office, the disclosures of which areincorporated herein by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates to a multilayer ceramic capacitor capableof having improved reliability through control of a size of a nickelparticle or a nickel oxide disposed in a side margin portion disposed ona side surface of a ceramic body, and a method of manufacturing thesame.

BACKGROUND

Generally, electronic components using a ceramic material, such as acapacitor, an inductor, a piezoelectric element, a varistor, athermistor, and the like, include a ceramic body formed of the ceramicmaterial, internal electrodes formed in the ceramic body, and externalelectrodes installed on surfaces of the ceramic body to be connected tothe internal electrodes.

Recently, in accordance with miniaturization and multi-functionalizationof electronic products, multilayer ceramic electronic components alsotend to be miniaturized and multifunctionalized. Therefore, a multilayerceramic capacitor having a small size and a high capacitance has beendemanded.

In order to miniaturize the multilayer ceramic capacitor and increasecapacitance of the multilayer ceramic capacitor, it has been required tosignificantly increase an electrode effective area (increase aneffective volume fraction required for implementing capacitance).

In order to implement the miniature and high-capacitance multilayerceramic capacitor as described above, in manufacturing the multilayerceramic capacitor, a method of significantly increasing areas ofinternal electrodes in a width direction of a body through a design thatdoes not have a margin by exposing the internal electrodes in the widthdirection of the body and completing the multilayer ceramic capacitor byseparately attaching side margin portions to electrode exposed surfacesof the multilayer ceramic capacitor in the width direction in a processbefore sintering after the multilayer ceramic capacitor is manufacturedhas been used.

However, in such a method, in a process of forming the side marginportion, a metal included in the internal electrode or an oxide of themetal may be disposed in the side margin portion, and reliability of themultilayer ceramic capacitor may be decreased due to the metal or theoxide of the metal.

In detail, an effect of decreasing a distance between adjacent internalelectrodes appears due to the metal or the oxide of the metal includedin the side margin portion, such that electric field concentration isgenerated, resulting in a short-circuit.

Therefore, research into technology capable of improving reliability ofa subminiature and high-capacitance multilayer ceramic capacitor bypreventing a short-circuit in the multilayer ceramic capacitor has beenrequired.

SUMMARY

An aspect of the present disclosure may provide a multilayer ceramiccapacitor capable of having improved reliability by controlling a sizeof a nickel particle or a nickel oxide disposed in a side margin portiondisposed on a side surface of a ceramic body, and a method ofmanufacturing the same.

According to an aspect of the present disclosure, a multilayer ceramiccapacitor may include: a ceramic body including dielectric layers andhaving first and second surfaces opposing each other, third and fourthsurfaces connecting the first and second surfaces to each other, andfifth and sixth surfaces connected to the first to fourth surfaces andopposing each other; a plurality of internal electrodes disposed in theceramic body, each exposed to the first and second surfaces and havingone end exposed to the third or fourth surface; and a first side marginportion and a second side margin portion disposed, respectively, on thefirst and second surfaces of the ceramic body, wherein a metal or ametal oxide is disposed in each of the first and second side marginportions, and a ratio of a diameter of the metal or the metal oxide to athickness of the dielectric layer is 0.8 or less.

According to another exemplary embodiment in the present disclosure, amethod of manufacturing a multilayer ceramic capacitor may include:preparing first ceramic green sheets on which a plurality of firstinternal electrodes patterns are disposed at predetermined intervals andsecond ceramic green sheets on which a plurality of second internalelectrodes patterns are disposed at predetermined intervals; forming aceramic green sheet multilayer body by stacking the first and secondceramic green sheets so that the first internal electrodes patterns andthe second internal electrodes patterns intersect each other; cuttingthe ceramic green sheet multilayer body to have side surfaces on whichdistal ends of the first internal electrodes patterns and the secondinternal electrodes patterns are exposed in a width direction; forming afirst side margin portion and a second side margin portion,respectively, on the side surfaces to which the distal ends of the firstinternal electrodes patterns and the second internal electrodes patternsare exposed; and preparing a ceramic body including dielectric layersand internal electrodes by sintering the cut ceramic green sheetmultilayer body, wherein a metal or a metal oxide is disposed in each ofthe first and second side margin portions, and a ratio of a diameter ofthe metal or the metal oxide to a thickness of the dielectric layer is0.8 or less.

According to still another aspect of the present disclosure, amultilayer ceramic capacitor may include: a ceramic body includingdielectric layers and having first and second surfaces opposing eachother, third and fourth surfaces connecting the first and secondsurfaces to each other, and fifth and sixth surfaces connected to thefirst to fourth surfaces and opposing each other; a plurality ofinternal electrodes disposed in the ceramic body, each exposed to thefirst and second surfaces and having one end exposed to the third orfourth surface; and a first side margin portion and a second side marginportion disposed, respectively, on the first and second surfaces of theceramic body, wherein a metal or a metal oxide is disposed in each ofthe first and second side margin portions, and a diameter of the metalor the metal oxide is smaller than a thickness of each of the dielectriclayers.

BRIEF DESCRIPTION OF DRAWINGS

The above and other aspects, features, and advantages of the presentdisclosure will be more clearly understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a schematic perspective view illustrating a multilayer ceramiccapacitor according to an exemplary embodiment in the presentdisclosure;

FIG. 2 is a perspective view illustrating an appearance of a ceramicbody of FIG. 1;

FIG. 3 is a perspective view illustrating a ceramic green sheetmultilayer body before the ceramic body of FIG. 2 is sintered;

FIG. 4 is a side view when viewed in direction B of FIG. 2;

FIG. 5 is an enlarged view of region S of FIG. 4; and

FIGS. 6A through 6F are schematic cross-sectional views and schematicperspective views illustrating a method of manufacturing a multilayerceramic capacitor according to another exemplary embodiment in thepresent disclosure.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the present disclosure will now bedescribed in detail with reference to the accompanying drawings.

FIG. 1 is a schematic perspective view illustrating a multilayer ceramiccapacitor according to an exemplary embodiment in the presentdisclosure.

FIG. 2 is a perspective view illustrating an appearance of a ceramicbody of FIG. 1.

FIG. 3 is a perspective view illustrating a ceramic green sheetmultilayer body before the ceramic body of FIG. 2 is sintered.

FIG. 4 is a side view when viewed in direction B of FIG. 2.

Referring to FIGS. 1 through 4, a multilayer ceramic capacitor 100according to the present exemplary embodiment may include a ceramic body110, a plurality of internal electrodes 121 and 122 disposed in theceramic body 110, and external electrodes 131 and 132 disposed on outersurfaces of the ceramic body 110.

The ceramic body 110 may have first and second surfaces 1 and 2 opposingeach other, third and fourth surfaces 3 and 4 connecting the first andsecond surfaces to each other, and fifth and sixth surfaces 5 and 6,which are upper and lower surfaces, respectively.

The first and second surfaces 1 and 2 refer to surfaces of the ceramicbody 110 opposing each other in a width direction, which is a seconddirection, the third and fourth surfaces 3 and 4 refer to surfaces ofthe ceramic body 110 opposing each other in a length direction, which isa first direction, and the fifth and sixth surfaces 5 and 6 refer tosurfaces of the ceramic body 110 opposing each other in a thicknessdirection, which is a third direction.

A shape of the ceramic body 110 is not particularly limited, but may bea rectangular parallelepiped shape as illustrated.

One ends of the plurality of internal electrodes 121 and 122 disposed inthe ceramic body 110 may be exposed to the third surface 3 or the fourthsurface 4 of the ceramic body 110.

The internal electrodes 121 and 122 may have a pair of first and secondinternal electrodes 121 and 122 having different polarities.

One ends of the first internal electrodes 121 may be exposed to thethird surface 3, and one ends of the second internal electrodes 122 maybe exposed to the fourth surface 4.

The other ends of the first internal electrodes 121 and the secondinternal electrodes 122 may be disposed to be spaced apart from thethird surface 3 or the fourth surface 4 by a predetermined interval.

First and second external electrodes 131 and 132 may be disposed on thethird and fourth surfaces 3 and 4 of the ceramic body 110, respectively,and may be electrically connected to the internal electrodes.

The multilayer ceramic capacitor 100 according to an exemplaryembodiment in the present disclosure may include the plurality ofinternal electrodes 121 and 122 disposed in the ceramic body 110,exposed to the first and second surfaces 1 and 2, and having one endsexposed to the third surface 3 or the fourth surface 4, and first andsecond side margin portions 112 and 113 disposed on side portions of theinternal electrodes 121 and 122 exposed to the first and second surfaces1 and 2, respectively.

The plurality of internal electrodes 121 and 122 may be disposed in theceramic body 110, the respective side portions of the plurality ofinternal electrodes 121 and 122 may be exposed to the first and secondsurfaces 1 and 2, which are surfaces of the ceramic body 110 in thewidth direction, and the first and second side margin portions 112 and113 may be disposed on the exposed side portions.

An average thickness of each of the first and second side marginportions 112 and 113 may be 2 μm or more to 10 μm or less.

According to an exemplary embodiment in the present disclosure, theceramic body 110 may include a laminate in which a plurality ofdielectric layers 111 are stacked and the first and second side marginportions 112 and 113 disposed on opposite side surfaces of the laminate,respectively.

The plurality of dielectric layers 111 may be in a sintered state, andadjacent dielectric layers may be integrated with each other so thatboundaries therebetween are not readily apparent.

A length of the ceramic body 110 may correspond to a distance from thethird surface 3 of the ceramic body 110 to the fourth surface 4 of theceramic body 110.

A length of the dielectric layer 111 may form a distance between thethird and fourth surfaces 3 and 4 of the ceramic body 110.

According to an exemplary embodiment in the present disclosure, thelength of the ceramic body 110 may be 400 to 1400 μm, but is not limitedthereto. More specifically, the length of the ceramic body 110 may be400 to 800 μm or may be 600 to 1400 μm.

The internal electrodes 121 and 122 may be disposed on the dielectriclayers 111, and the internal electrodes 121 and 122 may be disposed inthe ceramic body 110 with each of the dielectric layers interposedtherebetween, by sintering.

Referring to FIG. 3, the first internal electrodes 121 may be disposedon the dielectric layers 111. The first internal electrodes 121 may notbe entirely disposed on the dielectric layers in the length direction ofthe dielectric layers. That is, one end of the first internal electrode121 may be disposed up to the third surface 3 to be exposed to the thirdsurface 3, and the other end of the first internal electrode 121 may bedisposed to be spaced apart from the fourth surface 4 of the ceramicbody 110 by a predetermined interval.

The end portion of the first internal electrode exposed to the thirdsurface 3 of the ceramic body 110 may be connected to the first externalelectrode 131.

On the contrary to the first internal electrode, one end of the secondinternal electrode 122 may be exposed to the fourth surface 4 to beconnected to the second external electrode 132, and the other end of thesecond internal electrode 122 may be disposed to be spaced apart fromthe third surface 3 by a predetermined interval.

Four hundred or more internal electrodes may be stacked in order toimplement a high-capacitance multilayer ceramic capacitor, but thenumber of internal electrodes is not necessarily limited thereto.

The dielectric layer 111 may have the same width as that of the firstinternal electrode 121. That is, the first internal electrodes 121 maybe entirely disposed on the dielectric layers in the width direction ofthe dielectric layers 111.

According to an exemplary embodiment in the present disclosure, thewidth of the dielectric layer and the width of the internal electrodemay be 100 to 900 μm, but are not limited thereto. More specifically,the width of the dielectric layer and the width of the internalelectrode may be 100 to 500 μm or may be 100 to 900 μm.

As the ceramic body is miniaturized, a thickness of each of the sidemargin portions may have an influence on electrical characteristics ofthe multilayer ceramic capacitor. According to an exemplary embodimentin the present disclosure, each of the side margin portions may beformed at a thickness of 10 μm or less, such that characteristics of aminiaturized multilayer ceramic capacitor may be improved.

That is, each of the side margin portions may be formed at the thicknessof 10 μm or less, such that an overlapping area between the internalelectrodes forming capacitance may be secured as much as possible toimplement a high-capacitance and miniature multilayer ceramic capacitor.

The ceramic body 110 may include an active portion A contributing toforming capacitance of a capacitor, and upper and lower cover portions114 and 115 disposed as upper and lower margin portions on upper andlower surfaces of the active portion A, respectively.

The active portion A may be formed by repeatedly stacking a plurality offirst and second internal electrodes 121 and 122 with each of thedielectric layers 111 interposed therebetween.

The upper and lower cover portions 114 and 115 may be formed of the samematerial as that of the dielectric layer 111 and have the sameconfiguration as that of the dielectric layer 111 except that they donot include the internal electrodes.

That is, the upper and lower cover portions 114 and 115 may include aceramic material such as a barium titanate (BaTiO₃)-based ceramicmaterial.

Each of the upper and lower cover portions 114 and 115 may have athickness of 20 μm or less, but is not necessarily limited thereto.

In an exemplary embodiment in the present disclosure, the internalelectrodes and the dielectric layers, which are simultaneously cut andformed, may be formed at the same width. More detailed contents for thiswill be described below.

In the present exemplary embodiment, the dielectric layers may be formedat the same width as that of the internal electrodes, and the sideportions of the internal electrodes 121 and 122 may thus be exposed tothe first and second surfaces of the ceramic body 110 in the widthdirection.

The first and second side margin portions 112 and 113 may be disposed,respectively, on opposite side surfaces of the ceramic body 110 in thewidth direction to which the side portions of the internal electrodes121 and 122 are exposed.

Each of the first and second side margin portions 112 and 113 may havethe thickness of 10 μm or less. The smaller the thickness of each of thefirst and second side margin portions 112 and 113, the greater theoverlapping area between the internal electrodes disposed in the ceramicbody 110.

The thickness of each of the first and second side margin portions 112and 113 is not particularly limited as long as a short-circuit betweenthe internal electrodes exposed to the side surfaces of the ceramic body110 may be prevented, and may be, for example, 2 μm or more.

When the thickness of each of the first and second side margin portions112 and 113 is less than 2 μm, mechanical strength against externalimpact may be decreased, and when the thickness of each of the first andsecond side margin portions 112 and 113 exceeds 10 μm, the overlappingarea between the internal electrodes may be relatively decreased, suchthat it may be difficult to secure a high capacitance of the multilayerceramic capacitor.

In order to significantly increase capacitance of the multilayer ceramiccapacitor, a method of decreasing a thickness of each of the dielectriclayers, a method of increasing the number of stacked dielectric layerseach of which a thickness is decreased, a method of increasing acoverage of each of the internal electrodes, and the like, have beenconsidered.

In addition, a method of increasing the overlapping area between theinternal electrodes forming the capacitance has been considered.

In order to increase the overlapping area between the internalelectrodes, a margin portion region in which the internal electrodes arenot disposed needs to be significantly decreased.

Particularly, as the multilayer ceramic capacitor is miniaturized, themargin portion region needs to be significantly decreased in order toincrease the overlapping area between the internal electrodes.

According to the present exemplary embodiment, the internal electrodesmay be disposed over the entirety of the dielectric layers in the widthdirection of the dielectric layers, and each of the side margin portionsmay be set to 10 μm or less, such that the overlapping area between theinternal electrodes may be great.

Generally, as the number of stacked dielectric layers is increased,thicknesses of the dielectric layers and the internal electrodes may bedecreased. Therefore, a phenomenon in which the internal electrodes areshort-circuited may frequently occur. In addition, when the internalelectrodes are disposed on only portions of the dielectric layers, astep due to the internal electrodes may be generated, such that aninsulation resistance or reliability of the multilayer ceramic capacitormay be decreased.

However, according to the present exemplary embodiment, even though theinternal electrodes and the dielectric layers formed of thin films areformed, the internal electrodes may be entirely disposed on thedielectric layers in the width direction of the dielectric layers, andthe overlapping area between the internal electrodes may thus beincreased, such that the capacitance of the multilayer ceramic capacitormay be increased.

In addition, the step due to the internal electrodes may be decreased,such that the insulation resistance may be improved, and a multilayerceramic capacitor having excellent capacitance characteristics andexcellent reliability may be provided.

FIG. 5 is an enlarged view of region S of FIG. 4.

Referring to FIG. 5, in the multilayer ceramic capacitor according to anexemplary embodiment in the present disclosure, a metal or a metal oxide21 may be disposed in the first and second side margin portions 112 and113, a ratio of a diameter D of the metal or the metal oxide 21 to athickness td of the dielectric layer 111 may be 0.8 or less.

When the side margin portions are separately attached to electrodeexposed surfaces of the ceramic body 110 in the width direction in aprocess before sintering of processes of manufacturing the multilayerceramic capacitor as in an exemplary embodiment in the presentdisclosure, in a process of forming the side margin portions, a metalincluded in the internal electrode or an oxide of the metal may bedisposed in the side margin portions, and reliability of the multilayerceramic capacitor may be decreased due to the metal or the oxide of themetal.

In detail, an effect of decreasing a distance between the internalelectrodes appears due to the metal or the oxide of the metal generatedin the side margin portion, such that electric field concentration isgenerated, resulting in a short-circuit.

That is, when a neutral conductor permeates between the internalelectrodes having a potential difference, electric chargers in theneutral conductor may be rearranged depending on a property of theneutral conductor, and the neutral conductor in which the electriccharges are rearranged may have the same effect as that of an electrodeto decrease the distance between the internal electrodes, such thatelectric field strength between the internal electrodes may beincreased.

When the metal or the oxide of the metal, which is the neutralconductor, permeates into the side margin portion, the possibility thata short-circuit will occur may be increased due to an electric fieldstrength increase effect between the internal electrodes.

According to an exemplary embodiment in the present disclosure, aparticle size of the metal or the metal oxide 21 generated in each ofthe first and second side margin portions 112 and 113 may be controlledto predict an electric field concentration amount, resulting in areduction in the short-circuit.

In detail, the metal or the metal oxide 21 may be disposed in each ofthe first and second side margin portions 112 and 113, and the ratio ofthe diameter D of the metal or the metal oxide 21 to the thickness td ofthe dielectric layer 111 may be controlled to be 0.8 or less to controlan electric field increased in the internal electrodes, resulting in thereduction in the short-circuit.

The metal or the metal oxide 21 may be disposed in each of the first andsecond side margin portions 112 and 113, and when the ratio of thediameter D of the metal or the metal oxide 21 to the thickness td of thedielectric layer 111 exceeds 0.8, the diameter D of the metal or themetal oxide 21 having the same effect as that of the electrode may beincreased, such that the distance between the internal electrodes may bedecreased, resulting in the short-circuit.

On the other hand, in an exemplary embodiment in the present disclosure,the smaller the diameter D of the metal or the metal oxide 21, the lowerthe possibility that the short-circuit will occur. Therefore, a lowerlimit value of the ratio of the diameter D of the metal or the metaloxide 21 to the thickness td of the dielectric layer 111 is notparticularly specified.

In the metal or the metal oxide 21, the metal may be nickel (Ni), andthe metal oxide may be an oxide including nickel (Ni) and magnesium(Mg), but the metal and the metal oxide 21 are not necessarily limitedthereto.

When the first and second internal electrodes 121 and 122 include nickel(Ni), the metal or the metal oxide 21 disposed in each of the first andsecond side margin portions 112 and 113 may be nickel (Ni) or an oxideincluding nickel (Ni) and magnesium (Mg), as described above.

As another example, when the first and second internal electrodes 121and 122 include a metal other than nickel (Ni), the metal or the metaloxide 21 disposed in each of the first and second side margin portions112 and 113 may also be the metal other than nickel (Ni) or an oxide ofthe metal.

The metal or the metal oxide 21 may be disposed in regions of the firstand second side margin portions 112 and 113 adjacent to the dielectriclayer 111.

In an exemplary embodiment in the present disclosure, since the metal orthe metal oxide 21 may permeate into each of the first side marginportion 112 and the second side margin portion 113 when the side marginportions are separately attached to the electrode exposed surfaces ofthe ceramic body 110 in the width direction in the process before thesintering, as described above, and there is a limitation in diffusion ofthe metal or the metal oxide 21 into each of the side margin portions,the metal or the metal oxide 21 may be disposed in the regions of thefirst and second side margin portions 112 and 113 adjacent to thedielectric layer 111.

Particularly, the regions of the first and second side margin portions112 and 113 adjacent to the dielectric layer 111 may be regions betweenthe first and second internal electrodes 121 and 122.

When the metal or the metal oxide 21 is disposed in the regions betweenthe first and second internal electrodes 121 and 122 in the regions ofthe first and second side margin portions 112 and 113 adjacent to thedielectric layer 111, the electric field concentration between theinternal electrodes may be generated.

In other words, when separate margin portions are not attached as in amethod of manufacturing a multilayer ceramic capacitor according to therelated art, the possibility that the metal or the metal oxide will bedisposed in margin portions of the ceramic body in the width directionmay be low, and the possibility that the metal or the metal oxide willbe disposed particularly in margin portions of the ceramic body in thewidth direction, adjacent to the dielectric layer may be low.

Therefore, the feature that the metal or the metal oxide 21 is disposedin the regions of the first and second side margin portions 112 and 113adjacent to the dielectric layer 111 may be a unique phenomenon of thepresent disclosure, and in an exemplary embodiment in the presentdisclosure, the diameter of the metal or the metal oxide 21 may becontrolled to control the electric field concentration between theinternal electrodes, resulting in the reduction in the short-circuit.

Particularly, the multilayer ceramic capacitor according to an exemplaryembodiment in the present disclosure may be a subminiature andhigh-capacitance multilayer ceramic capacitor in which a thickness ofthe dielectric layer 111 is 0.4 μm or less and a thickness of each ofthe internal electrodes 121 and 122 is 0.4 μm or less.

As in an exemplary embodiment in the present disclosure, in a case ofthe subminiature and high-capacitance multilayer ceramic capacitor inwhich the dielectric layer 111 and the internal electrodes 121 and 122formed of thin films having the thickness of 0.4 μm or less are used, areliability problem due to the short-circuit caused by the electricfield concentration between the internal electrodes may be a veryimportant issue.

That is, as compared to the multilayer ceramic capacitor according tothe related art, technology according an exemplary embodiment in thepresent disclosure is applied to the subminiature and high-capacitancemultilayer ceramic capacitor in which the thickness of the dielectriclayer 111 is 0.4 μm or less and the thickness of each of the internalelectrodes 121 and 122 is 0.4 μm or less. Therefore, the thickness ofthe dielectric layer may be small, such that the distance between theinternal electrode may be small, resulting in an increase in thepossibility that the electric field will be concentrated.

In addition to the subminiature and high-capacitance multilayer ceramiccapacitor, in an exemplary embodiment in the present disclosure, theside margin portions may be separately attached to the electrode exposedsurfaces of the ceramic body 110 in the width direction in the processbefore the sintering. Therefore, in the process of forming the sidemargin portions, the metal or the metal oxide included in the internalelectrodes may be disposed in the side margin portions.

In this case, as described above, the metal or the metal oxide may serveas an electrode, such that the effect of further decreasing the distancebetween the internal electrodes appears. Therefore, the possibility thatthe short-circuit will occur due to the electric field concentration mayfurther be increased.

However, as in an exemplary embodiment in the present disclosure, in thesubminiature and high-capacitance multilayer ceramic capacitor in whichthe separate side margin portions are attached, the ratio of thediameter D of the metal or the metal oxide 21 to the thickness td of thedielectric layer 111 may be controlled to be 0.8 or less, such thatreliability of the multilayer ceramic capacitor may be improved even ina case in which the dielectric layer 111 and the first and secondinternal electrodes 121 and 122 are formed of the thin films having thethickness of 0.4 μm or less.

However, the thin films do not mean that the thicknesses of thedielectric layer 111 and the first and second internal electrodes 121and 122 are 0.4 μm or less, but may conceptually include that thethicknesses of the dielectric layer and the internal electrodes aresmaller than those of the multilayer ceramic capacitor according to therelated art.

In an exemplary embodiment in the present disclosure, in a method ofcontrolling the ratio of the diameter D of the metal or the metal oxide21 to the thickness td of the dielectric layer 111 to be 0.8 or less,the diameter D of the metal or the metal oxide 21 may be controlled bycontrolling a sintering temperature profile or controlling a temperaturerise speed in a sintering process after the first and second side marginportions 112 and 113 are disposed on the side surfaces of the ceramicbody 110 in the width direction.

Referring to FIG. 4, a ratio of a thickness tc2 of a region of the firstor second side margin portion 112 or 113 in contact with a distal end ofan internal electrode disposed at the outermost side portion to athickness tc1 of a region of the first or second side margin portion 112or 113 in contact with a distal end of an internal electrode disposed ina central portion, among the plurality of internal electrodes 121 and122 may be 1.0 or less.

A lower limit value of the ratio of the thickness tc2 of the region ofthe first or second side margin portion 112 or 113 in contact with thedistal end of the internal electrode disposed at the outermost sideportion to the thickness tc1 of the region of the first or second sidemargin portion 112 or 113 in contact with the distal end of the internalelectrode disposed at the central portion is not particularly limited,and may be 0.9 or more.

According to an exemplary embodiment in the present disclosure, thefirst or second side margin portion 112 or 113 may be formed byattaching a ceramic green sheet to the side surface of the ceramic bodyunlike the related art, and a thickness of the first or second sidemargin portion 112 or 113 at each position may thus be constant.

That is, in the related art, the side margin portion is formed in amanner of applying or printing a ceramic slurry, and a deviation of athickness of the side margin portion at each position is thus large.

In detail, in the related art, the thickness of the region of the firstor second side margin portion in contact with the distal end of theinternal electrode disposed at the central portion of the ceramic bodyis greater than those of other regions.

For example, in the related art, the ratio of the thickness of theregion of the first or second side margin portion in contact with thedistal end of the internal electrode disposed at the outermost sideportion to the thickness of the region of the first or second sidemargin portion in contact with the distal end of the internal electrodedisposed at the central portion is less than about 0.9, such that thedeviation of the thickness is large.

In the related art in which the deviation of the thickness of the sidemargin portion at each position is large, a portion occupied by the sidemargin portion in a multilayer ceramic capacitor having the same size islarge, such that a large size of a capacitance forming portion may notbe secured, resulting in difficulty in securing a high capacitance.

On the other hand, in an exemplary embodiment in the present disclosure,an average thickness of each of the first and second side marginportions 112 and 113 may be 2 μm or more to 10 μm or less, and the ratioof the thickness tc2 of the region of the first or second side marginportion 112 or 113 in contact with the distal end of the internalelectrode disposed at the outermost side portion to the thickness tc1 ofthe region of the first or second side margin portion 112 or 113 incontact with the distal end of the internal electrode disposed at thecentral portion among the plurality of internal electrodes 121 and 122may be 0.9 or more to 1.0 or less. Therefore, the thickness of the sidemargin portion may be small and the deviation of the thickness of theside margin portion may be small, such that a large size of thecapacitance forming portion may be secured.

In an exemplary embodiment in the present disclosure, the first orsecond side margin portion 112 or 113 may be formed by attaching theceramic green sheet to the side surface of the ceramic body unlike therelated art, and the thickness of the first or second side marginportion 112 or 113 at each position may thus be constant.

Therefore, a high-capacitance multilayer ceramic capacitor may beimplemented.

Meanwhile, referring to FIG. 4, a ratio of a thickness tc3 of a regionof the first or second side margin portion 112 or 113 in contact with anedge of the ceramic body 110 to the thickness tc1 of the region of thefirst or second side margin portion 112 or 113 in contact with thedistal end of the internal electrode disposed at the central portionamong the plurality of internal electrodes 121 and 122 may be 1.0 orless.

A lower limit value of the ratio of the thickness tc3 of the region ofthe first or second side margin portion 112 or 113 in contact with theedge of the ceramic body 110 to the thickness tc1 of the region of thefirst or second side margin portion 112 or 113 in contact with thedistal end of the internal electrode disposed at the central portion maybe 0.9 or more.

Due to the feature described above, a deviation of the thickness of theside margin portion in each region may be small, such that the largesize of the capacitance forming portion may be secured. Therefore, thehigh-capacitance multilayer ceramic capacitor may be implemented.

FIGS. 6A through 6F are schematic cross-sectional views and schematicperspective views illustrating a method of manufacturing a multilayerceramic capacitor according to another exemplary embodiment in thepresent disclosure.

According to another exemplary embodiment in the present disclosure, amethod of manufacturing a multilayer ceramic capacitor may include:preparing first ceramic green sheets on which a plurality of firstinternal electrodes patterns are disposed at predetermined intervals andsecond ceramic green sheets on which a plurality of second internalelectrodes patterns are disposed at predetermined intervals, forming aceramic green sheet multilayer body by stacking the first and secondceramic green sheets so that the first internal electrodes patterns andthe second internal electrodes patterns intersect each other, cuttingthe ceramic green sheet multilayer body to have side surfaces on whichdistal ends of the first internal electrodes patterns and the secondinternal electrodes patterns are exposed in a width direction, forming afirst side margin portion and a second side margin portion,respectively, on the side surfaces to which the distal ends of the firstinternal electrodes patterns and the second internal electrodes patternsare exposed, and preparing a ceramic body including dielectric layersand first and second internal electrodes by sintering the cut ceramicgreen sheet multilayer body, wherein a metal or a metal oxide isdisposed in each of the first and second side margin portions, and aratio of a diameter of the metal or the metal oxide to a thickness ofthe dielectric layer is 0.8 or less.

The method of manufacturing a multilayer ceramic capacitor according toanother exemplary embodiment in the present disclosure will hereinafterbe described.

As illustrated in FIG. 6A, the plurality of first internal electrodepatterns 221 having a stripe shape may be disposed at the predeterminedintervals on the ceramic green sheet 211. The plurality of firstinternal electrode patterns 221 having the stripe shape may be disposedin parallel with one another.

The ceramic green sheet 211 may be formed of a ceramic paste includingceramic powders, an organic solvent, and an organic binder.

The ceramic powder, which is a material having a high dielectricconstant, may be a barium titanate (BaTiO₃) based material, a leadcomposite perovskite based material, a strontium titanate (SrTiO₃) basedmaterial, or the like, and may be preferably a barium titanate (BaTiO₃)powder, but is not limited thereto. When the ceramic green sheet 211 issintered, the ceramic green sheet 211 may become a dielectric layer 111constituting the ceramic body 110.

The first internal electrode patterns 221 having the stripe shape may beformed of an internal electrode paste containing a conductive metal. Theconductive metal may be nickel (Ni), copper (Cu), palladium (Pd), oralloys thereof, but is not limited thereto.

A method of forming the first internal electrode patterns 221 having thestripe shape on the ceramic green sheet 211 is not particularly limited,but may be a printing method such as a screen printing method or agravure printing method.

In addition, although not illustrated, the plurality of second internalelectrode patterns 222 having a stripe shape may be disposed at thepredetermined intervals on another ceramic green sheet 211.

Hereinafter, the ceramic green sheet on which the first internalelectrode patterns 221 are disposed may be referred to as a firstceramic green sheet, and the ceramic green sheet on which the secondinternal electrode patterns 222 are disposed may be referred to as asecond ceramic green sheet.

Then, as illustrated in FIG. 6B, the first and second ceramic greensheets may be alternately stacked so that the internal electrodepatterns 221 having the stripe shape and the second internal electrodepatterns 222 having the stripe shape are alternately stacked.

Afterward, the first internal electrode patterns 221 having the stripeshape may become the first internal electrode 121, and the secondinternal electrode patterns 222 having the stripe shape may become thesecond internal electrode 122.

According to another exemplary embodiment in the present disclosure, athickness td′ of each of the first and second ceramic green sheets maybe 0.6 μm or less, and a thickness te of each of the first and secondinternal electrode patterns may be 0.5 μm or less.

Since the subminiature and high-capacitance multilayer ceramic capacitorin which the dielectric layer and the internal electrodes are formed ofthe thin films having the thickness of 0.4 μm or less is provided in thepresent disclosure, the thickness td′ of each of the first and secondceramic green sheets may be 0.6 μm or less, and the thickness te of eachof the first and second internal electrode patterns may be 0.5 μm orless.

FIG. 6C is a cross-sectional view illustrating a ceramic green sheetmultilayer body 220 in which the first and second ceramic green sheetsare stacked according to another exemplary embodiment in the presentdisclosure, and FIG. 6D is a perspective view illustrating the ceramicgreen sheet multilayer body 220 in which the first and second ceramicgreen sheets are stacked.

Referring to FIGS. 6C and 6D, the first ceramic green sheets on whichthe plurality of first internal electrode patterns 221 parallel with oneanother and having the stripe shape are printed and the second ceramicgreen sheets on which the plurality of second internal electrodepatterns 222 having parallel with one another and having the stripeshape are printed may be alternately stacked.

In more detail, the first ceramic green sheets and the second ceramicgreen sheets may be stacked so that central portions of the firstinternal electrode patterns 221 having the stripe shape, printed on thefirst ceramic green sheets and intervals between the second internalelectrode patterns 222 having the stripe shape, printed on the secondceramic green sheets overlap each other.

Then, as illustrated in FIG. 6D, the ceramic green sheet multilayer body220 may be cut across the plurality of first internal electrode patterns221 having the stripe shape and the plurality of second internalelectrode patterns 222 having the stripe shape. That is, the ceramicgreen sheet multilayer body 220 may be cut along cut lines C1-C1 andC2-C2 intersecting with each other to become multilayer bodies 210.

In more detail, the first internal electrode patterns 221 having thestripe shape and the second internal electrode patterns 222 having thestripe shape may be cut in the length direction to be divided into aplurality of internal electrodes having a predetermined width. In thiscase, the stacked ceramic green sheets may be cut together with theinternal electrode patterns. Therefore, the dielectric layers may beformed to have the same width as that of the internal electrodes.

In addition, the ceramic green sheet multilayer body may be cut atindividual ceramic body sizes along the cut lines C2-C2. That is, beforethe first and second side margin portions are formed, a laminate havinga bar shape may be cut at the individual ceramic body sizes along thecut lines C2-C2 to form a plurality of multilayer bodies 210.

That is, the laminate having the bar shape may be cut so that centralportions of the first internal electrodes and predetermined intervalsdisposed between the second internal electrodes, which overlap eachother, are cut by the same cut lines. Therefore, one ends of the firstand second internal electrodes may be alternately exposed to cutsurfaces.

Then, the first and second side margin portions may be disposed on firstand second side surfaces of the multilayer body 210.

Then, as illustrated in FIG. 6E, the first side margin portion 212 andthe second side margin portion (not illustrated) may be disposed on thefirst and second side surfaces of the multilayer body 210, respectively.

In detail, in a method of forming the first side margin portion 212, aceramic green sheet 212 for aside surface to which an adhesive (notillustrated) is applied may be disposed on a punching elastic material300 formed of rubber.

Then, the multilayer body 210 may be rotated by 90° so that the firstside surface of the multilayer body 210 faces the ceramic green sheet212 for a side surface to which the adhesive (not illustrated) isapplied, and the multilayer body 210 may then be pressed and closelyadhered to the ceramic green sheet 212 for a side surface to which theadhesive (not illustrated) is applied.

When the ceramic green sheet 212 for a side surface is transferred tothe multilayer body 210 by pressing and closely adhering the multilayerbody 210 to the ceramic green sheet 212 for a side surface to which theadhesive (not illustrated) is applied, the ceramic green sheet 212 for aside surface may be formed up to an edge portion of the side surface ofthe multilayer body 210 due to the punching elastic material 300 formedof the rubber, and the remaining portions may be cut.

FIG. 6F illustrates that the ceramic green sheet 212 for a side surfaceis formed up to the edge portion of the side surface of the multilayerbody 210.

Then, the multilayer body 210 may be rotated, and the second side marginportion may be disposed on the second side surface of the multilayerbody 210.

Then, the multilayer body 210 having the first and second side marginportions disposed on opposite side surfaces thereof, respectively, maybe calcinated and sintered to form the ceramic body including thedielectric layers and the first and second internal electrodes.

According to another exemplary embodiment in the present disclosure, theadhesive is applied to the ceramic green sheet 212 for a side surface,and the ceramic green sheet 212 for a side surface may thus betransferred to the side surface of the multilayer body 210 under a lowtemperature and low pressure condition unlike the related art.

Therefore, damage to the multilayer body 210 may be significantlydecreased, such that deterioration of electrical characteristics of themultilayer ceramic capacitor after the sintering may be prevented, andreliability of the multilayer ceramic capacitor may be improved.

In addition, the ceramic green sheet 212 for a side surface to which theadhesive is applied may be transferred to the side surface of themultilayer body 210 and be pressed in a sintering process to increaseclose adhesion between the multilayer body and the ceramic green sheetfor a side surface.

Then, external electrodes may be disposed, respectively, on the thirdside surface of the ceramic body to which the first internal electrodesare exposed and the fourth side surface of the ceramic body to which thesecond internal electrodes are exposed.

According to another exemplary embodiment in the present disclosure, athickness of the ceramic green sheet for a side surface may be small anda deviation of the thickness of the ceramic green sheet for a sidesurface may be small, such that the large size of the capacitanceforming portion may be secured.

In detail, an average thickness of each of the first and second sidemargin portions 112 and 113 after the sintering may be 2 μm or more to10 μm or less, and the deviation of the thickness of each of the firstand second side margin portions 112 and 113 at each position may besmall, such that the large size of the capacitance forming portion maybe secured.

Therefore, a high-capacitance multilayer ceramic capacitor may beimplemented.

A description for features that are the same as those in the exemplaryembodiment in the present disclosure described above will be omitted inorder to avoid an overlapping description.

Hereinafter, the present disclosure will be described in more detailthrough Experimental Example. However, Experimental Example is to assistin the detailed understanding of the present disclosure, and the scopeof the present disclosure is not limited by Experimental Example.

EXPERIMENTAL EXAMPLE

A multilayer ceramic capacitor according to Inventive Example wasmanufactured so that the metal or the metal oxide 21 is disposed in thefirst and second side margin portions 112 and 113, a ratio of a diameterD of the metal or the metal oxide 21 to a thickness td of the dielectriclayer 111 is 0.8 or less, and a multilayer ceramic capacitor accordingto Comparative Example was manufactured by the method according to therelated art.

In addition, a ceramic green sheet multilayer body was formed to formside margin portions by attaching ceramic green sheets for a sidesurface to electrode exposed portions of a green chip that does not havemargins due to exposure of internal electrodes in a width direction asin Comparative Example and Inventive Example.

Multilayer ceramic capacitor green chips having a 0603 size(width×length×height is 0.6 mm×0.3 mm×0.3 mm) were manufactured byapplying a predetermined temperature and pressure under a condition inwhich deformation of the chips is significantly suppressed to attach theceramic green sheets for a side surface to opposite surfaces of theceramic green sheet multilayer bodies.

Multilayer ceramic capacitor specimens of which the manufacture iscompleted as described above were subjected to a calcinating process ina nitrogen atmosphere at 400° C. or less, and were sintered under acondition of a hydrogen concentration of 0.5% H₂ or less at a sinteringtemperature of 1200° C. or less. Then, electrical characteristics of themultilayer ceramic capacitor specimens, such as a short-circuit, and thelike, were generally confirmed.

As a measurement result of the above experiment, it was confirmed thatin Comparative Example, a rate of defects such as short-circuits ishigh.

On the other hand, it may be confirmed that in Inventive Example inwhich the metal or the metal oxide 21 is disposed in each of the firstand second side margin portions 112 and 113, and the ratio of thediameter D of the metal or the metal oxide 21 to the thickness td of thedielectric layer 111 is 0.8 or less, a defective rate is less than 5%,such that reliability is excellent.

As set forth above, according to an exemplary embodiment in the presentdisclosure, a size of a nickel particle or a nickel oxide disposed inthe side margin portion disposed on the side surface of the ceramic bodymay be controlled to prevent the electric field concentration betweenthe internal electrodes, resulting in the reduction in theshort-circuit.

While exemplary embodiments have been shown and described above, it willbe apparent to those skilled in the art that modifications andvariations could be made without departing from the scope of the presentinvention as defined by the appended claims.

What is claimed is:
 1. A method of manufacturing a multilayer ceramiccapacitor, comprising: preparing first ceramic green sheets on which aplurality of first internal electrodes patterns are disposed atpredetermined intervals and second ceramic green sheets on which aplurality of second internal electrodes patterns are disposed atpredetermined intervals; forming a ceramic green sheet multilayer bodyby stacking the first and second ceramic green sheets, wherein the firstinternal electrodes patterns and the second internal electrodes patternsintersect each other; cutting the ceramic green sheet multilayer body tohave side surfaces on which distal ends of the first internal electrodespatterns and the second internal electrodes patterns are exposed in awidth direction; forming a first side margin portion and a second sidemargin portion each including nickel (Ni) metal particles therein, andattaching the formed first side margin portion and second side marginportion, respectively, on the side surfaces to which the distal ends ofthe first internal electrodes patterns and the second internalelectrodes patterns are exposed, before sintering; and preparing aceramic body including dielectric layers and internal electrodes bysintering the cut ceramic green sheet multilayer body, wherein a ratioof a diameter of the nickel (Ni) metal particles to a thickness of eachof the dielectric layers in the ceramic body is 0.8 or less.
 2. Themethod of claim 1, wherein the nickel (Ni) metal particles are disposedin regions of the first and second side margin portions adjacent to thedielectric layers.
 3. The method of claim 1, wherein a thickness of eachof the first and second ceramic green sheets is 0.6 μm or less, and athickness of each of the first and second internal electrode patterns is0.5 μm or less.
 4. The method of claim 1, wherein a ratio of a thicknessof a region of the first or second side margin portion in contact with adistal end of an outermost layer among the internal electrodes to athickness of a region of the first or second side margin portion incontact with a distal end of a central layer among the internalelectrodes ranges from 0.9 to 1.0.
 5. The method of claim 1, wherein aratio of a thickness of a region of the first or second side marginportion in contact with an edge of the ceramic green sheet multilayerbody to a thickness of a region of the first or second side marginportion in contact with a distal end of a central layer among theinternal electrodes ranges from 0.9 to 1.0.
 6. The method of claim 1,wherein an average thickness of each of the first and second side marginportions ranges from 2 μm to 10 μm.
 7. The method of claim 1, whereinthe ceramic body includes an active portion in which capacitance isformed by including the internal electrodes disposed to face each otherwith each of the dielectric layers interposed therebetween and coverportions disposed on upper and lower surfaces of the active portion,respectively, and a thickness of each of the cover portions is 20 μm orless.
 8. The method of claim 1, wherein the thickness of each of thedielectric layers is 0.4 μm or less, and a thickness of each internalelectrode is 0.4 μm or less.